999997543 has 2 divisors, whose sum is σ = 999997544. Its totient is φ = 999997542.

The previous prime is 999997489. The next prime is 999997561. The reversal of 999997543 is 345799999.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 999997543 - 2¹⁷ = 999866471 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999997643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499998771 + 499998772.

It is an arithmetic number, because the mean of its divisors is an integer number (499998772).

Almost surely, 2^999997543 is an apocalyptic number.

999997543 is a deficient number, since it is larger than the sum of its proper divisors (1).

999997543 is an equidigital number, since it uses as much as digits as its factorization.

999997543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24800580, while the sum is 64.

The square root of 999997543 is about 31622.7377530789. The cubic root of 999997543 is about 999.9991809993. Note that the first 3 decimals are identical.

It can be divided in two parts, 99999 and 7543, that multiplied together give a palindrome (754292457).

The spelling of 999997543 in words is "nine hundred ninety-nine million, nine hundred ninety-seven thousand, five hundred forty-three".